import json
with open(r"..\题库0.3\Problems.json","r",encoding = "utf8") as f:
    database = f.read()
idlist = list(json.loads(database).keys())
freeidlist = {}
for id in idlist:
    if not str(int(id)+1).zfill(6) in idlist:
        freeidlist[id] = ""
for id in freeidlist:
    largeridlist = [usedid for usedid in idlist if usedid > id]
    if not largeridlist == []:
        freeidlist[id] = str(int(min(largeridlist))-1).zfill(6)
    else:
        freeidlist[id] = "999999"
for id in freeidlist:
    print("首个空闲id:",str(int(id)+1),", 直至",freeidlist[id])